Machines used in the farming, construction, mining, power generation, and other similar industries commonly include a frame that supports an internal combustion engine, a work tool movably coupled to the frame, and at least one actuator coupled to the work tool and supplied with power by the engine. Such machines typically operate in harsh, dusty environments characterized by large amounts of airborne debris, such as dust and dirt. In such environments, it is desirable to remove the debris from the air before directing the air to the engine, so that the debris does not reduce the service life of the engine. To assist with this process, such machines typically include an intake air filter or other similar air cleaner configured to remove debris from the air upstream of the air intake of the engine. Further, to assist in prolonging the useful life of such air cleaners, some machines may also include a precleaner configured to remove relatively large debris from the air prior to cleaning the intake air with the air cleaner.
Some precleaners may include separators through which portions of the air enter the precleaner, and which use the air flow to separate the debris from the air. However, such separators may be designed to be effective at a particular air flow rate corresponding to operation of the engine at a relatively elevated output and a corresponding relatively high air flow rate into the intake of the engine. Thus, the separators may not be as effective at separating the debris from the air when the engine is operated at an output below the relatively elevated output. Thus, it may be desirable to increase the effectiveness of a precleaner at removing debris from intake air when an engine is operated at a relatively reduced output corresponding to a relatively reduced flow rate through the separators.
An example of an air induction tuning unit is described in U.S. Pat. No. 8,770,166 B2 to Tucker (“the '166 patent”). According to the '166 patent, a method and apparatus are provided for an air inlet duct of an internal combustion engine. The air inlet duct includes a tubular housing, and an inner wall has a plurality of perforations. The inner wall of the '166 patent is disposed within the tubular housing, such that the tubular housing includes at least two flow passages. A valve set is associated with a first flow passage of the at least two flow passages, and the valve set selectively controls airflow through the first flow passage, such that the first flow passage functions in at least one of a pass-through mode and a tuning mode.
Although the '166 patent purports to provide an air induction system that can respond to changes in engine load demands, it does not relate to improving the effectiveness of removing debris from air entering an intake air passage during changing outputs of an engine. The apparatus and precleaner disclosed herein may be directed to mitigating or overcoming one or more of the possible drawbacks set forth above.